ATHENS, Greece -- A two-man flight crew was killed on the Greek island of Evia when their plane slammed into a mountain after dropping water on a wildfire.

Witnesses reported seeing the yellow Canadair CL 415 water bomber swoop over the fire on the island northeast of Athens on Monday but falter while trying to gain altitude, Kathimerini reported Tuesday.

The men's deaths brought the toll of firefighters killed in Greece this year to seven, the report said.

Sweltering heat and dry conditions have been blamed on thousands of fires in the country, the report said.

In an unrelated interview with the newspaper hours before the crash, an unidentified firefighting pilot said crews were being stretched. He said in June and July of last year he had flown nine missions but had logged 75 flights in the same period this year.